Axial pin tumbler lock



May 5, 1970 P. M. TRAINOR 3,509,748

` AXIAL PIN TUMBLER Loox Filed April 24, 1968 4 Sheets-Sheet 1 P. M. TRAINOR AXIAL PIN TUMBLER LOCK May 5, 1970 y Filed April 24, 196s 4 sheets-sheet 2 a 47 34 i? 36535 47 54 33) 34,/6 55 7 7\ a 30 f J 5 J 3 42 ll I 45 42 4@ fg gli 25 e@ a@ f I Faim/{Mzvmaz' May 5, 1970 P. M. TRAINOR AXIAL PIN TUMBLER LOCK 4 Sheets-Sheet 5 Filed April 24, 1968 May 5, 1970 P. M. TRAINOR AXIAL PIN TUMBLER LOCK 4 Sheets-Sheet 4 PdrzclfMTrimaz' United States Patent U.S. Cl. 70--363 6 Claims ABSTRACT OF THE DISCLOSURE A pin tumbler lock in which a rotatable spindle received in the bore of a casing is locked against rotation by a number of tumbler pins circumferentially spaced around a circle concentric to the axis of the lock, and spring biased to positions extending across an interface between transversely disposed contiguous surfaces on the spindle and the casing. These contiguous surfaces are the bottom of a counterbore opening to the front end of the casing and the shoulder formed at the junction between a head 4portion and a stem portion of the spindle. An annular keyway in the head portion of the spindle receives a tubular key by which the tumblers are moved to unlocking positions freeing the spindle for rotation. The tumblers are removable from the rear end of the lock casing to enable yauthorized changing of the combination of the lock. A freely rotatable protective collar on the front end of the lock guards against the application of torsion on the spindle except by a proper key. Ball detents releasably hold the key in its fully inserted position against the thrust of the tumbler springs thereon, and another ball detent prevents insertion and/or withdrawal of the key except when the spindle is in 4a predetermined position of rotation.

This invention relates to pin tumbler locks and refers particularly to such locks in which the tumblers are circumferentially spaced around a circle concentric to the axis of the lock, to be moved to unlocked positions by a cylindrically tubular key inserted into an annular keyway. The George patent, No. 2,588,230, issued Mar. 4, 1952, illustrates a lock of this type.

The primary purpose and object of the invention is to provide a lock of the aforesaid type which is for all intents and purposes pick-proof and not vulnerable to defeat by the customary methods employed in defeating locks.

Another object of this invention is to provide a lock of the type set forth, in whic-h the combination can be quickly and easily changed.

It is also an object of this invention to provide a cylindrical tubular key operated lock in which the annular keyway is much narrower than has herebefore been possible in such locks.

Still another object of this invention is to provide a lock of the character described which is so designed and constructed that the key used to operate it has no protrusions whatsoever, either on its inner or outer cylindrical surface to engage in notches in the spindle, and wherein the key is nevertheless releasably held in its fully inserted position against the thrust of the tumbler spring thereon, even when the key is in its inserting and removing position of rotation; and wherein insertion and/ or withdrawal of the key is possible only when the spindle is in a defined position of rotation.

With these and other objects in mind, the manner in which the invention achieves its purpose will be appreciated from the following description and the accompanying drawings. This disclosure is intended merely to exemplify the invention. The invention is not limited to the particular structure disclosed, and changes can be made therein without departing from the invention.

The drawings illustrate two complete examples of the 3,509,748 Patented May 5, 1970 physical embodiments of the invention constructed according to the best modes so far devised for the practical application of the principles thereof and in which:

FIG. 1 is a view similar to FIGURE 1 but showing embodying this invention;

FIG. 2 is a vi ew similar to FIGURE 1 but showing the same in its unlocked condition by virtue of the presence therein of a proper key;

FIG. 3 is `a perspective view of the key, with the outer end portion of its handle broken away;

FIG. 4 is a cross sectional view through FIGURE 1 on the plane of the line 4 4;

FIG. 5 is a cross sectional view through FIGURE 2 on the plane of the line 5-5;

FIG. 6 is an exploded perspective View of the components of the lock;

FIG. 7 is a perspective view of the lock, viewing the same from the front;

FIG. S is a view partly in side elevation and partly in longitudinal section, illustrating a slightly modified embodiment of the invention; and

FIG. 9 is a perspective view of the protective collar of the modified embodiment of the lock.

Referring to the drawings, the numeral 5 designates the main body or casing of the lock. A spindle or cylinder 6 is mounted in the casing `and restrained against rotation therein by a plurality of pin tumblers 7, in the locked condition of the lock. Although the lock can be employed in different ways, and for different purposes, it is admirably suited to locking drawers or doors in their closed positions, in which event the body or casing 5 passes through a hole in a panel 8 and is fixed to the panel by clamping the portion of the panel immediately adjacent to the hole, between a fiange 9 on the front end of the casing and a nut 10 threaded on the casing. The cylinder or Spindle has Ia stem portion 11 protruding from the rear of the casing to actuate a latch bolt or other mechanism controlled by the lock.

To receive the spindle, the casing has a bore 12 which opens to the rear and a counterbore 13 which opens to the front end ofthe casing. The bottom 14 of this counterbore forms one of the two contiguous transversely disposed surfaces of an interface between the casing and the cylinder, and across which the pin tumblers extend in the locked condition of the lock. The other of the two surfaces of this interface is the shoulder 15 at the junction of the stem portion 11 of the spindle and a larger diameter head portion 16 which constitutes the fore part of the spindle and completely fills the counterbore so that the front faces of the spindle and casing are flush with one another. A C-washer 17 snapped into a groove 18 in the spindle, and bearing against the rear face of the casing, holds the spindle in place with its shoulder 15 abutting the bottom 14 of the counterbore to define the interface, which is depicted in FIGURES 1 and 2 by the line IF-IF.

The diameter of the counterbore 13 and the head portion 16 of the spindle is larger than the circle of pin tumblers, and the diameter of the spindle stem portion 11 and the bore 12 in which it is received, is smaller than that circle. Consequently, the drilled holes or wells 19 in which the pin tumblers are received can, and do, open to the bottom 14 of the counterbore as well as the rear face of the casing. Allen head set screws 20 close the rear ends of the wells and provide spring seats against which springs 21 react to yieldingly project the tumbler pins across the interface and into tumbler receiving pockets 22 drilled into `the head portion of the spindle from the shoulder 14.

Drive pins 23 slideably received in the pockets 22 provide means for displacing the tumbler pins from the pockets and aligning the abutting ends of the tumbler pins and their drive pins with the interface to free the spindle for rotation. It is, of course, to be understood that the several sets of tumbler pins and their drive pins are of different lengths so that the drive pins rnust be pushed back different distances to free the spindle for rotation. It is this which determines the combination of the lock.

An annular circular keyway Z5 in the head portion of the spindle opens to the front face of the spindle and communicates at its bottom with all of the tumbler receiving pockets 22. Accordingly, upon full insertion of a proper cylindrical tubular key 26 into the keyway, all of the pin tumblers can be brought to their positions freeing the spindle for rotation. As shown in FIG. 3, the key has circumferentially spaced notches 27 opening to its front end and to its peripheral surface, one for each tumbler. As the key is inserted, the front ends of the drive pins either enter these notches to be engaged by the bottoms of the notches, or are engaged by an unnotched edge portion of the key. In any event, upon full insertion of the key, all of the drive pins will be depressed the correct distance to align the abutting ends of all of the drive pins and their respective tumbler pins with the interface providing the key is properly bitted. With such alignment the spindle will be freed for rotation.

Rotation of the key is imparted to the spindle through the engagement of the sides of the notches 27 with the drive pins. In effect this interengagement between the drive pins and the sides of the notches constitutes a plurality of circumferentially spaced splines through which torque is applied to the spindle uniformly around its entire periphery and Without the need for a driving lug on the key entering a recess in the spindle as was the case in earlier locks of this general type.

This manner of drivingly connecting the key with the spindle is also conducive to reduction in the width of the keyway a feature which is quite significant from the standpoint of increasing the security of the lock, since it minimizes the probability of defeat by means of la cylindrical tubular hole cutting saw.

Attention is directed to the fact that the annular keyway is defined by the side wall of a bore 30 in the head portion of the spindle and the side of a cylindrical plug 31 solidly mounted in the bore 30 by driving a pin 32 which protrudes from the inner end of the plug into a hole in the bottom of the bore. The bottom of the key- Way which is lof course defined 1by the bottom of the bore 30 is spaced from the front face of the lock a distance such that the shortest drive pin-Which is engaged by an unnotched portion of the keywill be in its unlocking position when the key is bottomed in the keyway. This condition is illustrated in the upper half of FIG. 2.

As noted hereinbefore the rear ends of the tumbler wells 19 are closed by removable headless set screws 20. Hence the combination of the lock can be easily and quickly changed by simply removing one or more of the set screws allowing the tumbler pins and their drive pins to drop out through the open rear ends of the tumbler wells and replacing them with other sets of pins. Since this combination changing operation requires access to the rear of the lock it can only be performed by someone having a proper key; moreover it requires removal of the C-washer--which partially covers the mouths of the tumbler wells and the set screws therein.

Obviously to unlock the spindle :for rotation the key must be inserted into the keyway in one specific position of rotation. To define that proper rotational orientation between the lock and the key and to prevent insertion and/or withdrawal of the key except when the spindle is in any but the correct position a ball 33 is loosely seated in a hole 34 which extends radially through the annular wall 35 of the spindle head portion which surrounds the plug 31 and coacts therewith to define the annular keyway. The ball has a free though relatively close fit in the hole 34 and is of a diameter substantially corresponding to the distance between the inner surface of the keyway i.e. the side of the plug 31 and the side of the bore 30. Hence unless displaced the ball 33 bridges across and blocks the keyway. It can be so displaced only when the spindle is in a defined position of rotation which in the embodiment of the invention illustrated is a single position-namely, its locked position. In this position, the hole 34 aligns with a recess 36 in the wall of the bore 30 into which the ball may be pushed. The recess is deep enough to accommodate that part of the ball which exceeds the thickness of the wall 35. Hence, insertion of the key into the keyway is possible when the spindle is in its position in which the hole 34 aligns with the recess 36.

But it requires more than this for the ball 33 to identify the correct position of the key. This is done by providing the key with a hole 37 so located that when that hole is aligned with the ball and the ball drops into it, all the drive pin receiving pockets 27 of the key are correctly aligned with their respective drive pins. With the key thus positioned and shoved all the way into the keyway, the key can be turned in the casing, and since the drive pins in effect constitute torque transmitting splines, rotation of the key is imparted to the spindle.

inasmuch as withdrawal of the key entails displacement of the ball 33 from the keyway, it follows that the key and spindle must be returned to the position at which the hole 34 and the ball therein align with the recess 36. While this position can be felt for its attainment is facilitated by a pair of marker dots 38 and 39 on the front face of the casing and the spindle head. When these dots are opposite one another, as shown in FIG. 7, the spindle is in its key-inserting and key withdrawing position.

The marker dots 38-39 also cooperate with a finger 40 on the key to facilitate correct orientation of the key. This linger is angularly aligned with the hole 34 and since the marker dot 38 is angularly aligned with the recess 36, the alignment of the finger 40 with the dots identifies the correct position of rotation for the key.

Another feature of this invention resides in the provision of detent means to hold the key in its fully inserted psition against the thrust of the tumbler springs thereon, to thus obviate the need for holding the key in manually as it is turned. The detent means by which this advantage is gained consists of a pair of balls 42, smaller than the ball 33, one at each end of a cross bore 43 extending axially through the plug 31 near its front face. The cross bore 43 is large enough to accept the balls 42 which, however, are yieldingly urged out of the bore by a spring 44 confined between the two balls. Thus, in their normal positions, the balls 42 bear against the side of the bore 30 which defines the outer wall of the keyway and bridge across the keyway.

During insertion of the key, the balls 42 are pushed into the cross bore to snap into holes 45 in the key when the key is fully inserted. The entry of the balls into the holes 45 holds the key against outward displacement by the thrust of the tumbler springs; and to assure adequate retention of the key, the wall of the bore 30 preferably has recesses 46 opposite the ends of the cross bore 43 to partially receive the balls. These recesses permit the -balls to occupy more effective positions in the holes 45. Obviously, of course, the entry of the balls 42 into the holes 45 does not prevent manual withdrawal of the key.

Formation of the keyway by insertion of the plug 31 into the bore 30 in the head portion of the spindle has the advantage of facilitating the formation of the cross bore 43, which is done before the plug is driven home. But, more important, it enables the central part of the front face of the spindle to be hardened for resistance to drilling.

Protection against destruction of the lock by the application of torque to the casing is provided by a protective collar 47 which encircles the llange 9 at the front end of the casing. This collar, like the plug 31, is hardened steel. Its front face is ilush with that of the casing and spindle and it has an inwardly directed flange which lies behind the flange 9 to be confined between it and a panel on which the lock is mounted. Nothing but friction prevents rotation of the protective collar 47; hence if torque is applied to it in any Way, it simply turns without affecting the lock.

In the modiiied embodiment of the invention illustrated in FIG. 8, the protective collar 47' is dome or cup-shaped to afford even greater protection. Thus, in this case, the collar not only overlies the radially outer surface of the casing ange but also has a front wall portion 48 to cover the front face of the casing and the adjacent portion of the spindle. A hole 49 in the front wall 48 leaves the mouth of the annular keyway uncovered; and preierably the front face of the plug 31 is coplanar with the face of the front wall 48.

As best seen in FIG. 9, the dome or cup-shaped protective collar has a plurality of lugs or tangs 50 on its peripheral edge, which are bent down over the inner face of the iiange 9' to hold the collar in place, but this assembly cannot be effected until after the spindle has been assembled with the casing.

From the foregoing description, taken with the accompanying drawings, it will be apparent to those skilled in the art that this invention provides a greatly improved pin tumbler lock of the type controlled by a cylindrically tubular key.

What is claimed as my invention is:

1. In a pin tumbler lock of the type wherein la spindle rotatably received in a bored casing having front and rear ends is secured against unauthorized rotation, by a plurality of spring biased tumbler pins slidably mounted in tumbler wells in the casing for endwise movement parallel to the yaxis of the lock to and fromspring maintained locking positions extending across an interface between contiguous transversely disposed surfaces on the spindle and the casing and into tumbler receiving pockets in the spindle, the tumbler wells and pockets being circumferentially spaced around a circle concentric to the lock axis and the tumbler pins being displaceable from said pockets by a tubular cylindrical key acting through drive pins slideably received in said pockets, the improvement which comprises:

(A) the bore in the casing having a counterbore which opens to the front end of the casing and the bottom of which forms one of the transversely disposed surfaces of said interface;

(B) the spindle being inserted into the bore through the front end thereof and being stepped in diameter to provide a head portion which lls the counterbore and a stem portion which protrudes from the rear of the casing,

the shoulder at the junction between the head and stem portions abutting the bottomof the counterbore and forming the other surface of said interface, the diameter of the counterbore and the spindle head portion therein being greater than the circle of tumbler and drive pins, and the diameter of the stem portion and the core in which it is received being smaller than the circle of tumbler and drive pins;

(C) the head portion of the spindle having a narrow annular keyway which opens to the front face of the spindle and communicates at its bottom with the tumbler receiving pockets,

the keyway having concentric inner and outer walls, each of which is a part of the spindle, and the diameters of said keyway walls with respect to the circle of tumbler wells and pockets being such that the tumbler pockets open laterally to the keyway through its outer wall, while the inner wall of the keyway is spaced inwardly of the circle of tumbler wells and pockets, so that the drive pins in projecting axially into the keyway also partially bridge the keyway and provide circumferentially spaced torque transmitting splines adapted to be wedged between the outer wall of the keyway and the notched end of a tubular key inserted into the keyway to free the spindle for rotation; and

.(D) stop means on the stem of the spindle reacting against the rear end of the casing to hold the spindle in the casing with its shoulder abutting the bottom of the counterbore.

2. The pin tumbler lock of claim 1, further characterized by a protective collar encircling the front end of the bored casing and having a front wall portion covering the front face of the casing and the adjacent part of the front face of the head portion of the spindle,

said front wall portion of the protective collar having a round hole of a diameter corresponding to the outside diameter of the annular keyway.

3. The pin tumbler lock of claim 2, wherein the central portion of the head portion of the spindle which denes the inner wall of the annular keyway, is a hardened steel plug solidly secured to the portion of the spindle rearwardly of the bottom of the keyway, to coact with said protective cover in affording protection for the lock against defeat by drilling.

4. The pin tumbler lock of claim 1, further characterized by detent means on the head portion of the spindle to engage and releasably hold the key in its fully inserted tumbler depressing position against the thrust of the tumbler springs thereon, said detent means compnsmg:

a ball seated in a Well in the central part of the spindle head portion which defines the inner wall of the annular keyway,

and a spring in said well yieldingly urging the ball from the mouth of the well and against the outer wall of the annular keyway,

so that said ball bridges the keyway to be pushed into its well upon insertion of the key and to snap into a hole in the key when the key reaches its fully inserted posltion.

5. The pin tumbler lock of claim 4, wherein the well of the detent means is a cross bore extending diametrically through said central part of the spindle head portion,

and wherein there is a ball at each end of said cross bore and the spring is confined between the two balls.

6. The pin tumbler lock of claim 1, further characterized by means for preventing insertion and/or withdrawal of the key except when the spindle is in a predetermined position of rotation,

said means comprising a ball seated in a hole extending radially through the part of the head portion of the spindle which circumscribes the annular keyway and defines its outer wall,

said ball being of a diameter greater than the distance between the wall of the counterbore in the casing and the surface of the central part of the spindle head portion which defines the inner wall of the annular keyway,

so that said ball bridges the keyway and must be displaced to permit insertion of the key, the key having a hole to receive the ball, and the wall of the counterbore having a recess therein to receive the ball and permit its displacement from the keyway during insertion of the key and until the ball is received in the hole in the key and during withdrawal of the key,

the mouth of said recess being of a size to block any substantial movement of the ball circumferentially of the casing, so that the ball must be in the hole in the key before the key can be turned, and the key and spindle must be in a position of rotation aligning the ball with said recess before the key can be Withdrawn.

1,739,964 12/1929 Hainline 70-419 Machinist 70-417 Johnstone 70--363 Garniss 70--364 Wohrle 70-363 Wellekens 70-370 Adams 70-419 Greenwald 70-363 Kerr 70-421 RICHARD E. MOORE, Primary Examiner R. L. WOLFE, Assistant Examiner U.S. C1. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 509 748 Dated May 5 1970 Inventor(s) P .M Tra incr It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, lines 4 and 5 should read Figure l is a longitudinal sectional view through a lock embodying this SIGNED AND SENER Aue 251970 (SEAL) Attest:

mmm-m3 mw: x. m. AttestngOfr Commissioner o1 Patents FORM PO-1050 (lO-69) USCOMM DC 60376 pen usA covclnunn nmmuc. coince: un o-su-:u 

